Hypodermic syringe for blood tests

ABSTRACT

A syringe assembly for drawing a blood sample into a test tube suitable for blood analysis. The assembly includes an open-ended cylindrical tube secured at one end to a closure provided with a constricted neck of self-sealing elastomeric material and having an internal chamber therein communicating with the tube. Slidably disposed within the tube is a piston which is detachably coupled to a stem terminating in a handle whereby the piston may be shifted from an initial position sealing off said chamber to a final position adjacent the other end of the tube, the withdrawal of the piston creating a suction force. Also provided is an applicator having a yoke adapted to embrace the neck of the closure, and an L-shaped double-pointed needle secured at its junction to the yoke, the lateral arm of the needle penetrating the neck to enter the chamber therein, whereby blood flowing through the longitudinal arm of the needle which is injected in a vein of a patient is conducted into the neck chamber and from there into the tube to a level determined by the piston position. The piston serves as a stopper when the stem is detached therefrom and may be later removed by a puncturing tool which vents the stopper to facilitate its extraction from the tube.

United States Patent [1 1 Guerra Aug. 21, 1973 'HYPODERMIC SYRINGE FORBLOOD TESTS [76] Inventor: Luis A. Guerra, New York, NY.

[22] Filed: Mar. 10, 1971 [21] Appl. No.: 122,775

[52] US. Cl. 128/2 F, l28/DIG. 5, l28/2l4.4,

128/221, 128/276 [51] Int. Cl A6lb 5/14 [58] Field of Search 128/2 F, 2B, 2 G,

128/2 M, 2 R, DIG. 5, 215, 216, 218 R, 218 P, 218 D, 214.4, 221, 276

[56] References Cited UNITED STATES PATENTS 2,473,733 6/1949 Smith128/218 P 3,381,686 5/1968 Pierce 128/221 3,520,292 7/1970 Barr, Sr. etal.... 128/2 F 3,459,183 8/1969 Ring et a1. 128/214.4 3,090,383 5/1963Brooks 128/216 2,437,408 3/1948 Soet 128/276 3,013,557 12/1961 Pallotta128/218 3,613,663 10/1971 Johnson. 128/2 R 2,847,995 8/1958 Adams128/214 Primary Examiner-Kyle L. I-Iowell Attorney-Michael Ebert [5 7]ABSTRACT A syringe assembly for drawing a blood sample into a test tubesuitable for blood analysis. The assembly includes an open-endedcylindrical tube secured at one end to a closure provided with aconstricted neck of self-sealing elastomeric material and having aninternal chamber therein communicating with the tube. Slidably disposedwithin the tube is a piston which is detachably coupled to a sternterminating in a handle whereby the piston may be shifted from aninitial position sealing off said chamber to a final position adjacentthe other end of the tube, the withdrawal of the piston creating asuction force. Also provided is an applicator having a yoke adapted toembrace the neck of the closure, and an L-shaped double-pointed needlesecured at its junction to the yoke, the lateral arm of the needlepenetrating the neck to enter the chamber therein, whereby blood flowingthrough the longitudinal arm of the needle which is injected in a veinof a patient is conducted into the neck chamber and from there into thetube to a level determined by the piston position. The piston serves asa stopper when the stem is detached therefrom and may be later removedby a puncturing tool which vents the stopper to facilitate itsextraction from the tube.

5 Claims, 17 Drawing Figures PATENTED M1821 I975 SHEET 1 0F 2 INVENTOR.10/5 14. Goa-22A PATENTED M182] I813 SHEH 2 BF 2 INVENTOR. 40/6 amea PR/02 4/2 T A WHEY 1 HYPODERMIC SYRINGE FOR BLOOD TESTS BACKGROUND OF THEINVENTION This invention relates generally to hypodermic techniques forobtaining blood samples, and more particularly to a hypodermic syringeassembly adapted to draw blood from a patient and to feed it directlyinto a test tube.

Medical procedures carried out in a hospital, which entail some degreeof care and skill, are timeconsuming and may contribute significantly tothe expenses of medical care. With present-day shortages of doctors,nurses, and trained hospital personnel, the time factor involved in anyprocedure reduces the working time available for carrying out otheressential functions, so that it is not only the cost of a procedure interms of labor and material which must be taken into account, but alsothe loss of valuable professional time.

In the modern hospital, blood tests are carried out on a large scale andthe price of equipment used for this purpose and the time involved inthe procedure are important operating cost factors. Existingblood-sampling procedures are deficient in many respects and give risenot only to a loss in time but also to trauma and defective bloodanalysis.

Since in a hospital most patients are confined to bed, in order toanalyze a patients blood, a sample must be taken at bedside and conveyedto the hospital laboratory. In a typical multi-story hospital structureand logistics of collecting and transporting blood samples from thehospital rooms to the laboratory are fairly complicated.

It is for this reason that some hospitals are equipped with a network ofpneumatic conduits, making it possible to convey test tubes from therooms directly to the laboratory under pneumatic pressure at high speed.The pneumatic conveyor makes use of multi-cell cartridges designed toaccommodate test tubes and to pass through the conduits. But, as willlater be explained, present blood-sampling techniques do not lendthemselves to pneumatic conveyance; hence it becomes necessary tohand-carry the blood samples, with an attendant loss in time.

The traditional means for taking a blood sample is the hypodermicsyringe which can be used not only to draw blood from a patient, butalso to inject medication. The standard syringe includes a cylindricaltube having a piston therein which, when pulled by an operator, createsa suction force drawing blood into the tube through a nozzle coupled toa hypodermic needle. The amount of blood drawn into the tube isdetermined by the extent to which the piston is withdrawn. A syringe hasmany practical advantages, for it gives the operator the feeling ofbeing inside the vein, and blood may be drawn at a gentle or fast rate,as desired, in the amount needed or available and with little trauma.

However, in order to carry out blood tests, the blood in the syringemust be transferred to a test tube that can be centrifuged and istherefore suitable for blood analysis. Thus, in order to use a standardsyringe for blood tests, a sample must be drawn from the patient and theblood contained in the syringe transferred to a test tube which is thensent to the testing laboratory. Since it is not possible to include ananti-coagulating agent in the syringe, this agent must be laterintroduced in the sample, and it a delay occurs, as is sometimes thecase, co-

agulation may result and the sample rendered defective.

In an attempt to overcome the drawbacks of standard syringes, a vacuumcontainer has been developed, making it possible to obtain a bloodsample in a test tube and to obviate the need to transfer the sample.

In a vacuum chamber an evacuated test tube having a removable,self-sealing rubber stopper, operates in conjunction with a multi-sampleneedle, one end of which is injected into the stopper whereby blood fromthe patient is sucked into the tube, which may then be sent to thelaboratory where it is centrifuged. Not only does the vacuum containerdo away with the need for blood transfer, but it has another importantadvantage in that an anti-coagulant may be stored in the evacuated tubeto intermingle with the blood at the moment the sample is taken, therebyavoiding the delayed contact.

Nevertheless, the vacuum container has a number of serious drawbacks. Tobegin with, the operator has no feeling of being inside the vein andwhen switching tubes on the multisample needle, he may lose the vein.Also, in coupling the vacuum container to the needle, the pressure mustbe applied along the needle axis to penetrate the stopper. This pressureis transmitted to the patient and may be traumatic. Another difficultywith the vacuum container is that the vacuum may collapse the vein, andit then becomes impossible to draw blood. In the event the needleassociated with the Vacutainer does not penetrate the vein but insteadmakes contact with tissue, the suction force may traumatize this tissue.Also, the operator has no control over the rate at which the blood isdrawn.

In addition to the above drawbacks, with the vacuum container, one hasno control over the amount of blood drawn into the tube, for this isdetermined by a predetermined vacuum pressure. Since to minimize thepossibility of vein collapse, the vacuum must be moderate, the amount ofblood drawn into the tube is generally such as to only partially tillthe tube. Because of the free air space in a vacuum container containinga blood sample, the sample is subject to a mixing action and cannot,therefore, be sent to the laboratory by way of a pneumatic system. Thereason for this is that the agitation of the sample within the free airspace produces air bubbles in the blood which promote the destruction ofred blood cells and therefore interferes with test procedures.

Since the traditional syringe provides better control in extractingblood samples, whereas the vacuum container is useful in that itprovides a pre-closed test tube which may be quickly filled and maycontain an anticoagulant for immediate contact with the blood, thepresent practice is to use the syringe to draw the sample and to injectthe blood into a Vacutainer.

The cost of this procedure therefore includes the cost of both syringesand vacuum container. Moreover, because vacuum container cannot beconveyed pneumatically, the sample must be transported to the laboratoryby hospital personnel. In some instances the delay encountered inobtaining a blood analysis may jeopardize the life of a patient.

SUMMARY OF THE INVENTION In view of the foregoing, it is the main objectof this invention to provide a hypodermic syringe assembly adapted todraw blood from a patient directly into a test tube, which tube has nofree air space, and may be transmitted pneumatically to a laboratorywithout rendering the blood unsuitable for analysis.

More specifically, an object of the invention is to provide a syringeassembly wherein the piston is manipulated by a detachable stem, andalso serves as the removable stopper of the test tube, the piston beingcaused to assume a position in the tube avoiding an air space therein.

Still another object of the invention is to provide a removable pistonof the above type which may be used to replace the existing stopper in avacuum container to avoid a free space in the test tube thereof and topermit pneumatic conveyance of the vacuum container tube.

Yet another object of the invention is to provide an improved catheteradapted to cooperate with a syringe assembly in accordance withtheinvention.

Also an object of the invention is to provide a disposable hypodermicsyringe assembly which may be manufactured and assembled at low cost.

Briefly stated, in a syringe assembly in accordance with the invention,an open-ended cylindrical tube is secured at one end to a closureincluding a constricted neck having an internal chamber, the closurebeing formed of self-sealing elastomeric material which may bepenetrated by a hypodermic needle. Slidably disposed within the tube isa piston also formed in part of similar elastomeric material, the pistonbeing manipulated by a detachable stem terminating in a handle, wherebythe piston position in the tube is initially such as to seal off theneck chamber.

Also provided is an applicator having a U-shaped yoke adapted to embracethe neck of the closure, the applicator including an L-shaped,double-pointed needle whose junction is embedded in the yoke, the needlehaving a lateral arm which penetrates the neck to enter the chamber, anda longitudinal arm for vein injection, whereby blood flows from thepatient into the neck chamber and from there into the tube.

The amount of blood drawn intothe tube is controlled by the pistonposition, no air space being created between the piston and the sample.To convey the sample to the laboratory, the tube is detached from theapplicator and the stem is detached from the piston, v

OUTLINE OF THE DRAWING For a better understanding of the invention, aswell as other objects and further features thereof, reference is made tothe following detailed description to be read in conjunction with theaccompanying drawing, in which:

FIG. 1 is a perspective view, partly in section, of a hypodermic syringeassembly in accordance with the invention, the syringe being shown inits initial state;

FIG. 2 shows the same syringe assembly atter a blood sample has beentaken;

FIG. 3 separately shows the tube and closure of the syringe assembly;

FIG. 4 separately shows the detachable stem and piston of the syringe;

FIG. 5 shows the manner in which the stem is detached from the pistonafter a sample has been taken;

FIG. 6 is a front view of the applicator and its relationship to theclosure of the syringe;

FIG. 7 is a side view of the same applicator;

FIG. 8 is a perspective view showing the manner in which the applicatoris coupled to the syringe closure;

FIG. 9 is a section of the puncturing tool for removing the piston;

FIG. 10 illustrates the manner in which the puncturing tool is used;

FIG. 11 shows a conventional vacuum container containing a blood sample;

FIG. 12 shows how the puncturing tool is used to replace the vacuumcontainer stopper with a piston in accordance with the invention;

FIG. 13 illustrates the position of the piston in the Vacutainer;

FIG. 14 is a sectional view of a catheter in accordance with theinvention;

FIG. 15 is a lateral view of the catheter;

FIG. 16 shows the catheter in cooperation with a syringe assembly inaccordance with the invention; and

FIG. 17 shows the catheter used for the transfusion of fluid.

DESCRIPTION OF THE INVENTION Referring now to FIGS. 1 to 8, there isshown a syringe assembly in accordance with the invention, comprising anopen-ended cylindrical tube 10 which may be fabricated of glass or of asuitable transparent, disposable plastic material. The lower end of thetube is attached to a closure generally designated by numeral 11, formedof self-sealing elastomeric material, such as neoprene rubber. Theclosure is constituted by a coupling shoulder 11A having an annulargroove therein which frictionally receives the end'of the syringe tube,the shoulder being integral with a constricted neck 11B anda bulboushead 11C. Neck 11B is provided with an internal chamber 19 whichcommunicates with tube Telescoping within tube 10 is a stem 12, one endof which is flanged to define a handle 13, the other end having a hollowscrew 14 extending axially therefrom, the screw being threadablyreceived within the central socket 15A of a piston 15. Piston 15 is inthe form of I a ring, which may be made of high-strength, rigid plasticmaterial, the ring fitting within a cup formed of selfsealing resilientelastomeric material or rubber. The cup is provided with peripheralcorrugations to effect a fluid-tight seal with the inner wall of tube10. By pulling handle 13, one may slide piston 15 up the tube to createa suction force to draw blood therein to a maximum level indicated bystop-mark 16.

The syringe cooperates with a hypodermic applicator constituted by aU-shaped yoke member I7 preferably made of plastic material such aspolypropylene, adapted to frictionally embrace neck 11B of closure 11,and an L-shaped, double-pointed hypodermic needle 18, the junction ofwhose arms is embedded in yoke 17. The short or lateral arm 18A of theneedle lies at right angles to the longer longitudinal arm 18B, wherebywhen neck 11B is laterally pressed onto yoke 17, the short armpenetrates the neck and enters internal chamber 19 therein, whichcommunicates with tube 10. Because of this lateral coupling arrangement,no axial pressure is produced which is transmitted to the patient, andno trauma is caused thereby.

Chamber 19 is filled with a suitable anti-coagulant agent and isinitially sealed by piston 15. However, when the hypodermic needle arm18B pierces a vein or artery and the piston is pulled away from theclosure by handle 13 to create a suction force, blood flows into chamber19 by way of short arm 18A where it intermingles with the anti-coagulantagent therein.

After the desired amount of blood has been drawn into tube 10, theclosed syringe tube is disconnected from applicator l7 and, as shown inFIG. 5, stem 12 is disconnected from piston 15, this being accomplishedsimply by rotating the stem to unscrew it from the piston. The detachedsyringe tube is therefore now a sealed test tube, and because there isno air space therein and the piston 15 now functions as a stopper, itmay be transmitted pneumatically to the hospital laboratory. At thispoint, another syringe tube may be coupled to the applicator, which isstill in place, and another blood sample may be taken.

In the laboratory, the piston 15 must be removed so that the blood canbe analyzed. Extraction of the piston 15 from tube 10 is effected by apuncturing tool 20, as shown in FIGS. 9 and 10, which includes a hollowshank A provided with an extemally-threaded hollow screw 20B and apuncturing needle 21 projecting axially therefrom. When screw 20B isthreaded into the socket 15A of piston 15, as shown in FIG. 10, theneedle 21 penetrates the piston to vent the tube, making it thenpossible to pull out the piston which otherwise, by reason of airpressure, resists displacement.

The puncturing tool 20 also makes it possible to replace the stopper 22in a conventional vacuum container tube 23, as shown in FIGS. 11, 12 and13, with a piston 15 serving as a stopper in a manner whereby the newstopper may be brought into direct contact with the blood to precludefree air space.

Thus as shown in FIG. 11, with the conventional vacuum container, thereis an air space 24 between stopper 22 and the blood sample 25, whereaswhen this stopper is replaced by piston 15, which is forced down thevacuum container tube until it makes contact with the blood, the airspace is totally eliminated. The same puncturing tool is used to insertthe piston and to later remove it; in both cases the puncturing needlevents the piston to facilitate its passage up or down the tube.

By replacing the standard stopper of the vacuum container with a piston,as described herein, it then becomes possible to pneumatically conveythe vacuum container to the laboratory, thereby effecting majoreconomies in transit time, so that a rapid blood analysis may be made.

Referring now to FIGS. 14 to 17, there is shown an improved form ofcatheter which may be used in conjunction with a syringe assembly of thetype previously disclosed, to take blood samples or for purposes ofblood or fluid transfusion.

The catheter is constituted by a short funnel 26 of a suitable plasticmaterial, which may be transparent, the mouth of the funnel being closedby a removable stopper 27. Adjacent the lower end of the funnel there isformed a small outlet port 28 which is inclined relative to thelongitudinal axis of the funnel and is coupled to a flexible cathetertube 29 of a suitable high-grade, inert plastic material, such aspolyvinyl chloride or Tef- Inn.

On the other side of the funnel, in a position in registration with theoutlet, is a small inlet port 50, within which is inserted a plug 31 ofrubber or other selfsealing material. The common axis of the inlet andoutlet ports lies at an oblique angle relative to the longitudinal axisof the funnel.

When, as shown in FIG. 16, the needle arm 18B of the syringe assembly isinjected into plug 31, the needle passes through outlet port 28 andcoaxially into catheter tube 29.

Once the catheter is in place, and one then desires to transfuse bloodor any other fluid into the patient, stopper 27 is removed as shown inFIG. 17, and the fluid line 32 from a fluid supply 33 is coupled to themouth of funnel 26. At this point one removes the needle and thesyringe, and fluid from the supply then flowsinto the vein.

Because of its configuration, the catheter disclosed herein does notrequire a long needle in order to enter a vein, and it is thereforepossible to use a regular sampling needle as a tutor. Multi-samples ofblood may be taken directly into test tubes without having to usestandard syringes as intermediaries. Because no plug is pulled out whentaking samples, no loss of blood is encountered when using the catheter.

The syringe tube acts as a view chamber for the catheter, therebyeliminating the need for a special view chamber to indicate whether thecatheter is in place, and there is no need to remove the end of anintravenous device already set in place, in order to take blood samples.

It is to be noted that after blood has been drawn into a syringe of thetype shown in FIGS. 1 to 7, the danger exists that through inadvertenceor carelessness, one may then push the stem of the piston toward thewrong end that is, toward closure 11. This action will produce apositive pressure causing a flow of blood mixed with anti-coagulant backinto the vein of the patient. Should the anti-coagulant be toxic innature, its injection into the patient may have adverse effects.

This drawback is avoided by installing a simple oneway security valve atthe outlet'of chamber 19. This valve is adapted to admit the flow ofblood and anticoagulant from chamber 19 into tube 10, but to preventcountercurrent flow. In practice, the valve may take the form of a flap11D of elastomeric material, secured to closure 11 at the outlet chamber19, as shown in FIGS. 3 and 7. This flap is caused to open when stem 12is pulled out to create a suction force whereby blood is free to flowfrom chamber 19 into tube 10. But when stem 12 is pushed in to producepositive pressure, valve 11D closes to block the chamber passage.

The security valve is only necessary when an anticoagulant is employed,but not otherwise. When the syringe is used for injection purposes, thevalve is omitted.

While there have been shown and described, preferred embodiments of ahypodermic syringe for blood tests, in accordance with the invention, itwill be appreciated that many changes and modifications may be madetherein, without, however, departing from the essential spirit of theinvention.

I claim:

1. A syringe assembly for drawing blood samples, said assemblycomprising:

A. an open-ended cylindrical tube of transparent material,

B. a needle-piereeable closure secured to one end of said tube, saidclosure being formed of self-sealing material and having a couplingshoulder attached to said end of said tube, a constricted neck extendingfrom said shoulder and having an internal chamber communicating througha passage in said shoulder with said tube and a bulbous head extendingfrom the neck,

C. a piston slidable in said tube from an initial position abutting saidcoupling shoulder and blocking the passage therein to seal said chamberto a final position adjacent the other end of said tube,

D. a stern telescoping in said tube and terminating in a handle outsideof said tube at said other end of said tube, said stem being coupled tosaid piston and being detachable therefrom whereby after said piston ispulled by said handle to said final position drawing a desired amount ofblood in said tube, said stem may be detached from said piston whichthen serves as a stopper, and

E. an applicator frictionally engaging said closure for filling saidtube with a blood sample and being removable therefrom when the filledtube is to be transmitted, said applicator having a U-shaped yokeengaging said neck of said closure laterally,

said applicator being provided with an L-shaped, double-pointed needlewhose junction is secured to said yoke, said needle having a lateral armwhich penetrates said neck to enter said chamber and a longitudinal armfor injection.

2. An assembly as set forth in claim 1, wherein said closure is formedof rubber.

3. An assembly as set forth in claim 1, wherein said piston is formed inpart of needle-puncturable selfsealing material.

4. An assembly as set forth in claim 1, wherein said tube is made of adisposable transparent plastic material.

5. A catheter cooperating with the longitudinal arm of the applicator inthe syringe assembly as set forth in claim 1, said catheter comprising afunnel adjacent whose lower end is an outlet port coupled to a cathetertube and an inlet port in registration with said outlet port, said inletport having a self-sealing needlepenetrable plug receiving thelongitudinal arm of said applicator, the upper end of said funnel beingprovided with a removable stopper.

1. A syringe assembly for drawing blood samples, said assemblycomprising: A. an open-ended cylindrical tube of transparent material,B. a needle-pierceable closure secured to one end of said tube, saidclosure being formed of self-sealing material and having a couplingshoulder attached to said end of said tube, a constricted neck extendingfrom said shoulder and having an internal chamber communicating througha passage in said shoulder with said tube and a bulbous head extendingfrom the neck, C. a piston slidable in said tube from an initialposition abutting said coupling shoulder and blocking the passagetherein to seal said chamber to a final position adjacent the other endof said tube, D. a stem telescoping in said tube and terminating in ahandle outside of said tube at said other end of said tube, said stembeing coupled to said piston and being detachable therefrom wherebyafter said piston is pulled by said handle to said final positiondrawing a desired amount of blood in said tube, said stem may bedetached from said piston which then serves as a stopper, and E. anapplicator frictionally engaging said closure for filling said tube witha blood sample and being removable therefrom when the filled tube is tobe transmitted, said applicator having a U-shaped yoke engaging saidneck of said closure laterally, said applicator being provided with anL-shaped, double-pointed needle whose junction is secured to said yoke,said needle having a lateral arm which penetrates said neck to entersaid chamber and a longitudinal arm for injection.
 2. An assembly as setforth in claim 1, wherein said closure is formed of rubber.
 3. Anassembly as set forth in claim 1, wherein said piston is formed in partof needle-puncturable self-sealing material.
 4. An assembly as set forthin claim 1, wherein said tube is made of a disposable transparentplastic material.
 5. A catheter cooperating with the longitudinal arm ofthe applicator in the syringe assembly as set forth in claim 1, saidcatheter comprising a funnel adjacent whose lower end is an outlet portcoupled to a catheter tube and an inlet port in registration with saidoutlet port, said inlet port having a self-sealing needle-penetrableplug receiving the longitudinal arm of said applicator, the upper end ofsaid funnel being provided with a removable stopper.